Linear motion Flashcards
Scalar
Measurements that only have magnitude (size).
Vector
Measurements that have magnitude (size) and direction.
Examples of a vector
Weight, acceleration, displacement, velocity and momentum.
Examples of a scalar
Mass, distance and speed.
Describe how vectors are usually represented
- With the use of an arrow.
- The longer the arrow, the greater the size.
- Direction is shown by point and line of application
What is mass and how is it measured.
The quantity of matter the body possesses.
Measured in KG.
How is weight different to mass
Weight is the force on a given mass due to gravity
Measured in N
How to calculate Weight
Weight (N) = Mass (Kg) x Gravity (9.8)
Distance
The path a body takes as it moves from start to finish
Displacement
Shortest route in a straight line between start and finish
Speed
A measurement in m/s of the body’s movement per unit of time with o reference to direction
How is speed calculated.
Speed (m/s) = distance covered (m) ÷ time taken (s).
Velocity
Measured in m/s and is the rate of change of displacement
How is velocity calculated
Velocity (m/s) = displacement (m) ÷ time taken (s)
What does the distance time graph look like for a stationary performer
What does the distance time graph look like for a performer constant rate but distance is changing
/
What does the distance time graph look like for a performer who is decelerating
curve
___________
/
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What does the distance time graph look like for a performer who is accelerating
curve
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How to calculate gradient of graph
changes in the y / changes in the x
What does the velocity time graph look like for a performer travelling at constant velocity
What does the velocity time graph look like for a performer travelling at increased velocity (acceleration)
curve
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What does the velocity time graph look like for a performer travelling at decreased velocity (deceleration)
curve
___________
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If the velocity time graph goes in to the negative x and y axis what does that mean the performer is doing
Change in direction
Acceleration
Measured in /s2 and is the rate of change of velocity
How to calculate acceleration
Change in velocity (m/s) / Time (s)
How to calculate the change in velocity
(Final velocity - Initial velocity) / Time
How to calculate momentum
Momentum (kgm/s) = mass (kg) X velocity (m/s)
External force
Force that comes from outside the body
Example of an external force
Friction, air resistance and weight.
Internal force
Force generated by the contraction of skeletal muscles
Example of an internal force
The force generated as the quads contract concentrically to extend the knee in a jump
Give the two vertical forces.
Weight and reaction force
When does a reaction force occur.
When two bodies are in contact with one another.
Give the two horizontal forces.
Friction and air resistance.
Friction
Occurs when 2 or more bodies are in contact with one aother
What are the two types of frictional force
Static and sliding
What 3 factors can affect friction
1) Surface characteristics of the 2 bodys
2) Temperature of the 2 surfaces
3) Mass of objects
Air resistance
A force that acts in the opposite direction to the motion of a bod travelling through the air
What does air resistance depend on
- Velocity of moving body
- Cross sectional area of moving body
- The shape and surface characteristics of a moving body
Drag
Net force
This is the resultant force acting on a body when all other forces have been considered
How to calculate impulse
Impulse = Force x Time
Net impulse
A combination of positive and negative impulses
